Architectural glass
products play a major role in the comfort of the living and working
environment of today's homes and commercial office spaces. By
providing natural daylight, views of the surroundings, thermal
comfort and design aesthetics, glass usage and condition often
affect our selection of where we live, work, shop, play and seek
education.

Architectural glass
products must be properly cleaned during construction activities and
as a part of routine maintenance in order to maintain visual and
aesthetic clarity. Since glass products can be permanently damaged
if improperly cleaned, glass producers and fabricators recommend
strict compliance with the following procedures for properly
cleaning glass surfaces.

As dirt and residue
appear interior and exterior glass surfaces should be thoroughly
cleaned. Concrete or mortar slurry that runs down (or is splashed
on) glass can be especially damaging and should be washed off as
soon as possible. Before proceeding with cleaning determine whether
the glass is clear, tinted or reflective. Surface damage is more
noticeable on reflective glass as compared with other glass
products. If the reflective surface is exposed either on the
exterior or interior special care must be taken when cleaning, as
scratches to the reflective glass surface can result in coating
removal and a visible change in light transmittance. Cleaning tinted
and reflective glass surfaces in direct sunlight should be avoided
since the surface temperature can be excessively hot for optimum
cleaning. Cleaning should begin at the top of the building and
continue to the lower levels to reduce the risk of leaving residue
and cleaning solutions on glass at the lower levels. Cleaning
procedures should also ensure that the wind is not blowing the
cleaning solution and residue onto already cleaned glass.

Cleaning during
construction activities should begin with soaking the glass surfaces
with clean water and soap solution to loosen dirt or debris. Using a
mild non-abrasive commercial window washing solution, uniformly
apply the solution to the glass surfaces with a brush, strip washer
or other non-abrasive applicator. Immediately following the
application of the cleaning solution a squeegee should be used to
remove all of the cleaning solution from the glass surface. Care
should be taken to ensure that no metal parts of the cleaning
equipment touch the glass surface and that no abrasive particles are
trapped between the glass and the cleaning materials. All water and
cleaning solution residue should be dried from window gaskets,
sealants and frames to avoid the potential for deterioration of
these materials as the result of the cleaning process.

It is strongly
recommended that window washers clean a small area or one window
then stop and examine the surface for any damage to the glass and/or
reflective coating. The ability to detect certain surface damage,
i.e. light scratches can vary greatly with the lighting conditions.
Direct sunlight is needed to properly evaluate a glass surface for
damage. Scratches that are not easily seen with a dark or gray sky
may be very noticeable when the sun is at a certain angle in the sky
or when the sun is low in the sky.

The glass industry
takes extreme care to avoid glass scratches by protecting all glass
surfaces during glass manufacturing and fabrication as well as
during all shipping and handling required to deliver the glass to
the end user. A large percentage of damaged glass results from
non-glass trades working near glass. This includes painters,
spacklers, ironworkers, landscapers, carpenters and others who are
part of the construction process. They may inadvertently lean tools
against the glass, splash materials onto the glass and/or clean the
glass incorrectly, any of which can permanently damage glass.

One of the common
mistakes made by non-glass trades people including glass cleaning
contractors is their use of razor blades or other scrappers on a
large portion of the glass surface. Using two, three, four, or five
inch and larger blades to scrape a window clean carries a large
probability of causing irreparable damage to glass.

The entire industry
of glass manufacturers, fabricators, distributors, and installers
neither condones nor recommends widespread scraping of glass
surfaces with metal blades or knifes. Such scraping will often
permanently damage or scratch the glass surfaces. When paint or
other construction materials cannot be removed with normal cleaning
procedures a new one-inch razor blade may need to be used only on
non-coated glass surfaces. The razor blade should be used on small
spots only. Scraping should be done in one direction only. Never
scrape in a back and forth motion as this could trap particles under
the blade that could scratch the glass. This practice can cause
hairline concentrated scratches that are not normally visible when
looking through the glass but are be visible under certain lighting
conditions.

Jobsite storage and
construction conditions can lead to stains on the glass surface.
Cleaning and removal of such stains may require the use of a more
aggressive cleaning solution and procedure. If conditions are found
that cannot be cleaned using the above procedures contact the glass
supplier for guidelines on stain removal.

Members of the Glass
Association of North America (GANA) publish information relating to
jobsite protection and cleaning of architectural glass products. In
order to ensure long-term performance of the glass in a building
GANA encourages glazing contractors, general contractors, building
management and owners to be aware of conditions that can damage
glass and to follow the handling and cleaning guidelines provided by
the glass producer and fabricator.

Consult the GANA web
site at www.glasswebsite.com
for additional information on glass and glazing applications and
links to members providing additional technical resources.

The Glass Association
of North America (GANA) has produced this Glass Information Bulletin
solely to provide general information on basic proper procedures for
cleaning architectural glass products. The Bulletin does not purport
to state that any one particular type of glass cleaning process or
procedure should be used in all applications or even in any specific
application. The user of this Bulletin has the responsibility to
ensure the cleaning instructions from the glass supplier are
followed. GANA disclaims any responsibility for any specific results
relating to the use of this Bulletin, for any errors or omissions
contained in the Bulletin, and for any liability for loss or damage
of any kind arising out of the use of this Bulletin.

Quick-Reference
Guide to Cleaning Architectural Glass Products
The following Do's and Do Not's are offered as a supplement to the
Glass Association of North America (GANA) Glass Informational
Bulletin - Proper Procedures for Cleaning Architectural Glass
Products:

The following are
things to DO:

DO clean glass when
dirt and residue appear

DO determine if
coated glass surfaces are exposed

DO exercise special
care when cleaning coated glass surfaces

DO avoid cleaning
tinted and coated glass surfaces in direct sunlight

DO start cleaning
at the top of the building and continue to lower levels

DO soak the glass
surface with a clean water and soap solution to loosen dirt and
debris

DO use a mild,
non-abrasive commercial window cleaning solution

DO use a squeegee
to remove all of the cleaning solution

DO dry all cleaning
solution from window gaskets, sealants and frames

DO clean one small
window and check to see if procedures have caused any damage

DO be aware of and
follow the glass supplier's specific cleaning recommendations

DO caution other
trades against allowing other materials to contact the glass

DO watch for and
prevent conditions that can damage the glass

DO read the entire
GANA bulletin on glass cleaning before starting to clean glass

The following are
things to NOT do:

DO NOT start
cleaning without reading the entire GANA bulletin on glass
cleaning

DO NOT use scrapers
of any size or type for cleaning glass

DO NOT allow dirt
and residue to remain on glass for an extended period of time

DO NOT begin
cleaning glass without knowing if a coated surface is exposed

DO NOT clean tinted
or coated glass in direct sunlight

DO NOT allow water
or cleaning residue to remain on the glass or adjacent materials

DO NOT begin
cleaning without rinsing excessive dirt and debris

DO NOT use abrasive
cleaning solutions or materials

DO NOT allow metal
parts of cleaning equipment to contact the glass

DO NOT trap
abrasive particles between the cleaning materials and the glass
surface

DO NOT allow other
trades to lean tools or materials against the glass surface